Lift trucks and other material handling devices which comprise a frame, a mast assembly pivotally mounted adjacent a bottom end thereof to the frame and powering means for rotating the mast assembly to tilt forwardly and rearwardly are of course quite well known to the prior art. Such assemblies however have a number of problems. The seriousness of these problems is greatly increased in heavy duty units as, for example, in log-moving lift trucks. One problem is that forces delivered to the mast assembly due to the lift truck or other such device being run over rough ground can lead to bending of structural members and damage of hydraulic lines, hydraulic cylinders and the like. Another and very important problem is that the tilt cylinder can be subjected to severe twisting forces caused by uneven load distribution as occurs when an uneven load is being transported or by crowding of a single carriage fork against a resistant object.